搜题请搜索小程序“爱下问搜题”
问题 选择题

在一密闭容器中进行反应：2SO2（g）+O2（g）

2SO3（g） 测得开始时，SO2、O2、和SO3的浓度分别为0.2mol∙L-1、0.1mol∙L-1、0.2mol∙L-1，在反应过程中不断测该容器中各物质的浓度，下列测定数据肯定不正确的是（　　）

A．O2为0.15mol∙L-1

B．SO2为0.25mol∙L-1

C．SO3为0.4mol∙L-1

D．O2、SO3的浓度相等

答案

该题2SO2（g）+O2（g）⇌2SO3（g）是一个可逆反应．假设SO2（g）和O2（g）全部转化为SO3（g）． 

      2SO2（g）+O2（g）⇌2SO3（g） 

初始    0.2mol∙L-1 0.1mol∙L-1 0.2mol∙L-1

变化    0.2mol∙L-1 0.1mol∙L-1 0.2mol∙L-1

终了     0             0          0.4mol∙L-1

 

假设SO3（g）全部转化为SO2（g）和O2（g）

         2SO2（g）+O2（g）⇌2SO3（g） 

初始    0.2mol∙L-1 0.1mol∙L-1 0.2mol∙L-1

变化    0.2mol∙L-1 0.1mol∙L-1 0.2mol∙L-1

终了    0.4mol∙L-1 0.2mol∙L-1                  0

该反应是一个可逆反应，无论向正反应方向进行还是向逆反应方向进行．实际不可能100%转化．

综上情况可知：0＜n（SO2）＜0.4mol∙L-1 ；0＜n（O2）＜0.2mol∙L-1 ；0＜n（SO3）＜0.4mol∙L-1 ．

A．O2为0.15mol∙L-1 在范围内，不符合条件，故A不选；

B．SO2为0.25mol∙L-1在范围内，不符合条件，故B不选；

C．SO3为0.4mol∙L-1 不在范围内，故C测定数据肯定不正确，故C选；

D．O2、SO3的浓度相等，需平衡向逆反应方向进行：

         2SO2（g）+O2（g）⇌2SO3（g） 

初始    0.2mol∙L-1 0.1mol∙L-1 0.2mol∙L-1

变化    2X          X               2X

终了  0.2+2X        0.1+X             0.2-2X

O2、SO3的浓度相等；0.1+X=0.2-2X  

              X=0.1/3 mol∙L-1

 此时：

SO2：0.2+2X=0.2+0.2/3  mol∙L-1；O2：0.1+X=0.1+0.1/3； SO3：0.2-0.1/3 mol∙L-1

符合0＜n（SO2）＜0.4mol∙L-1 ；0＜n（O2）＜0.2mol∙L-1 ；0＜n（SO3）＜0.4mol∙L-1 范围．

故D不选．

故选C．

阅读理解

It was a beautiful Sunday morning, and Maggie and I were returning from our walk through the woods．We were only a couple of blocks from home when I spotted a cell phone and a credit card sitting on the road．We took them home．We always find amazing things on the street and she looks upon them as a movable feast-a chicken wing here or a barbecue rib （肋骨）there．

I found another cell phone a few years back, too, and called a number in its phone book．I explained the situation to the guy who answered．He said it was his sister’s and that he’d come to pick it up, which he did．

And that was that．No verbal thank-you, no written thank-you, no “here’s a box of chocolates” thank-you．

I didn’t have time to call anyone on my latest found cell phone．I was pouring myself coffee when it started to shake and dance across the kitchen counter．

“Who’s this?” someone asked when I picked up．

“Who’s this?” I countered（反问）．“Sarah?”

She was surprised at my knowing her name until she realized her name was on the credit card．“Could you send them to me?” she asked．

She lives in Arlington, which is 2 miles from my house．

“Hmm, no, ”I replied, adding that I thought she could come to get them, and that if I wasn’t at home, they would be in my mailbox．

A day later, when I was out for a run, someone got them back．There wasn’t even a piece of paper put in the mailbox with “Thanks” on it．In this age of e-mail and cell phone, there’s really no excuse．Years ago, I found something more precious than a $100 bill on the street：a driver’s license．I saw  that its owner lived a couple of blocks from me, so I called him up．He asked whether I could slip the license through his front door．

“I guess I could, ”I replied．

And that was that．

小题1:What is the relationship between Maggie and the writer?

A．Wife and husband

B．Daughter and father

C．Teacher and student

D．Master and pet dog小题2:．How many experiences are mentioned by the writer to return things to the losers?

A．3

B．4

C．5

D．6小题3:How did the writer know Sarah’s telephone number?

A．From her telephone’s phone book

B．From her credit card

C．From her e-mail

D．From her driver’s license小题4:The writer wants to tell us through the unusual stories,

A．we should return the things we picked to the losers

B．people don’t know how to appreciate others in the age of e-mail and cell phone

C．people would learn to appreciate persons who provide help for you

D．the advance of society makes people lose some virtues
查看答案
问答题 简答题

棉花播种前需要做好哪些准备工作？
查看答案